Over the last year I’ve spent a lot of time trying to find conductive plastic that has resistance properties even close to wire. What I’ve found is currently there is nothing on the market that comes even close. Although a plastic “Described” as conducting is offered by quite a few venders the conductivity it pretty bad. If you are making an anti-static pad or a Faraday cage your OK but for most circuits it’s not practical, basically it just plastic with infused Carbon Black.
I did spend some time trying to make my own and I did get some good batches but I had a real hard time with getting consistent batches. If you interested I used Multi Walled Carbon Nanotubes and infused them is standard PLA. believe it or not nanotubes are pretty cheap now. I got mine from “CheapTubes.com“. Yes, believe it or not that’s the name of the company. I tried a bunch of combinations but my greatest success was with MWNT’s around the 30-50nm range. Basic method is to take existing 3D printing plastic and mix it with “Dichloromethane” this liquefies it and after a time just remove to stopper off your mixing bottle and the dichloromethane will evaporate leaving just the plastic infused with the nanotubes. Now all you have to do is get it back in 3D printer plastic form. To do that I just built a 3D printing extruder.
If someone comes up with a better way to do it let me know but the best I was able to get was about 200 ohms per inch, still not what I was looking for but way better then stuff available on the market now.
When selecting the extruder for the RepRapPro be sure to take a little extra time before just selecting the Mini extruder as I did. My line of though was that it was smaller and would look better on the printer which, looking back on it was a pretty stupid reason to make a section. By and large I consider my selection of the Mini extruder to be my biggest misstate with regard to that printer build. Here is what I’ve fount;
- The mini is really small. it’s small so the gear teeth are small which means your prints need to be dead on. There is no room for even a small deviation.
- The threading channel hole for the plastic is static. Simply put it’s a printed diameter hole. threading and working with it is a pain.
- the Friction adjustment is not really all that effective.
- The mounting of the extruder on the printer itself can effect the friction applied to the plastic being extruded. (Really an pain)
So simply put for me the choice of the Mini extruder was really bad! It’s just my opinion but you’ve been warned, choose the curtain on the left and go with the normal, proven Huxley_Extruder.
in the RepRapPro model files it’s the directory Modified_RepRapPro_Huxley_Extruder not the Mini you want. (Picture on left)
OpenSCad is a great open source 3D modeling tool for 3D printable models but it’s weak point is the code editor and since everything is code based with no GUI tool set you have to look elsewhere for a good editor. I’ve found for myself that Notepad++ has some great plug-ins. It’s a windows tool but Ubuntu has “Wine” a windows compatibility emulator that works great with it and is available in the Ubuntu Software Center. After installing OpenSCad and Notepad++ go to Thingiverse to pick up the XML Config files for OpenSCad and follow the directions provided along with them. Remember to configure OpenScad for Automatic Reload and Compile and also in the view tab you can hide the default OpenSCad editor which you won’t be using anymore. I’ve found the whole experience of using OpenSCad to be much better since I moved on from the default editor.
This is a little heads up on an issue I ran into a while back regarding my 3D printer and Ramps 1.4. The symptom where that although the printer worked when connected to the USB and external power the LCD went blank. When using just the external power supply it didn’t function correctly. The most obvious thing was when connected just though the USB to the computer the LCD interface worked but once external power was applied the LCD went blank. After a lot of looking around I found it was all about a 5V power regulator on the mega board. In fact on the board below you can see a three prong power regulator right there on the lower left next to the power plug. I ordered a new regulator “10 Pcs AMS1117 LM1117 1117 5.0 H342TE 5V 1A Voltage Regulator SOT-223 from eBay and was good to go. In all honestly I just bought the new board on amazon for 40 dollars and fixed the old one later for a backup.
Since I’m fundamentally cheap and have an unreasonable phobia regarding Microsoft products over the years I’ve been attempting to find the best tool for my 3D modeling restricted to the open source community. So, here is what I’ve found, as far as machine operating systems go I finally settled Ubuntu, its simple to use and more then covers my needs. CAD software is a lot more challenging, I’ve started to become convinced that software companies are using the Microsoft platform as a way to enhance there licensing enforcement. Lets face it, if the software only runs on Windows then it much more likely the end user will pay for it since they already payed for the operating system and if it was pirated they can ride right along with the Microsoft’s legal team. So anyway my final tool box ends up being OpenSCad for most models. I thought I’d hate the command line driven tool but with a plug-in from Notepad++ it ends up being easy to use and very strait forward, it’s no wonder it’s the top file type format you see when going to Thingiverse. If I’m looking to really build something complex with a lot of moving parts I use FreeCad and yes, I know it use to suck but the last few releases have really cleaned things up. Last but not least for “Art” I use Blender and honestly it’s not all that often I feel the need to go down the Blender path. Blender is great but for 3D printing models it clunky and time consuming. Last but not least I have two favorite slicers. Number one for single extruder prints and dual extruder prints for support I’ve found KISSlicer is the way to go, I know the web site doesn’t look like much, but the slicer is free and trust me you will not be disappointed. Things get a little more complicated for dual extruder printing when your not using one of the extruders for support, If thats the model type I’m working with I use Slic3r.
OK, thats all my rambling for the moment, if you have any other solutions that are Linux based and free of cost let me know.
This new way of measuring the Z axis is great for providing perfect prints every time but there are a few things you need to keep in mind. First at the moment the base Marlin firmware although configurable does not really work right. Use https://github.com/jcrocholl/Marlin/tree/fsr at least thats what got it working for me. I used 5 of FORCE SENSING RESISTOR,0.5 INCH ,CIRCLE,1oz-22LB,FLEXIBLE from Jameco.
Another thing I learned is you do need to secure them with two sided tape (You know the stuff white and kind of thick), it’s not just to secure the resistors but also it helps to distribute the force, trust me on this you need the tape!
Now I used a pretty simple way of wiring it all up. I just took 5 FSR sensors and put them in parallel and wired them all up through an old contact switch sensor I had from an earlier printer build. That way I had a little sensor board with an led to work with. I did try during my testing to wire the thing right to the Ramps 1.4 Z switch plugs as well that that worked too. The resistor pretty much works as a simple switch, off with no pressure and no real resistance when pressure applied.
Last but not least keep in mind that you have to update your slicer to put the new scripting in pre-Gcode, you need this or the slicer default firmware pretty much overrides all the work you did. Here is the Code,
G28 X0 Y0 ;home X and Y
G29 ;probe bed
G90; set absolute coordinates
G92 E0; reset extruder distance
G1 Z5 F300 ;move platform down 5mm
G1 X145 Y145 F3000 ; move to back right corner
By far the greatest resource for 3D printing enthusiasts is the printing 3D printing site of www.reprap.org, originally developed to facilitate the development of self replication of 3D printers it has gone over the years to become the principle goto site for enthusiasts for general technical info and for insight and support building 3D printing systems.